Battering rams are used by firefighters and police officers in order to quickly gain access through locked or barricaded doorways in buildings. Past battering rams are described, for example, in U.S. Pat. No. 5,329,685 to Gillespie. Battering rams generally suffer from being too heavy to operate and failing to provide enough power to break open a door on the first shot.
Pneumatic devices, such as the device described in the Gillespie patent, can provide a higher striking velocity and thus a higher peak force that assists in breaking through a door on the first swing. However, such designs suffer from several disadvantages. First, the supply of compressed air is located internally and is therefore not rapidly interchangeable. Second, the sear mechanisms are generally unstable and of poor mechanics. Third, the venting and charging of gases in Gillespie is not easily managed by the end user, which can result in delays in re-charging or re-setting the device that can translate into negative consequences for the user.